Movements of people suffering e.g. from dementia and mental disorders at home, in a hospital building, nursing home, service flat, departments or corresponding premises thereof can be monitored e.g. by means of a wristband to be worn round the wrist and able to be wirelessly connected by radio path with access control base stations attached to a building. A display provided in the system's control room may show a current state in the building, and the system may give an alarm if the person takes the wristband off or tries to leave without permission.
Since any equipment to be attached to a person is inconvenient and it is difficult by means of the above solution to detect e.g. if a person becomes immobile, solutions based on motion detection and pressure detection have been developed. When motion is monitored in a room occupied by a person, it is possible to detect if the person is immobile for too long. In such a case, it may be assumed that he or she has fallen, for instance, and an alarm is given. When a person's bed is provided with a pressure sensor, his or her dwelling in the bed may be monitored.
However, such a monitoring system presents problems. By motion detectors it is impossible to detect the actual instance of falling, but the assumption of falling is based on detecting no motion. This may cause unnecessary alarms and, in a real problem situation, too slow an alarm. The placement of the pressure sensor in the bed may interfere with the use of the bed, such as making and cleaning the bed. In addition, a large pressure sensor in particular may impede the person's sleep. Different positions of the person may also affect whether or not the person is detected to be in the bed. Further, if an object having the shape and/or weight of a human being placed in the bed, the system may assume that the person is in the bed even if this is not the case. Thus, a need exists to develop the monitoring system and the related monitoring method.